Method of treating unattached leather soles



Patented Oct. 5, 1937 METHOD OF TREATING UNATTACHED LEATHER SOLES William P. Crockett, Brookline, Mass, assignor to United Shoe Machinery Corporation, Paterson, N. J., a corporation of New Jersey No Drawing.

11 Claims.

This invention relates to methods of making shoes and more particularly to methods of treating unattached leather soles.

For reasons well known to shoe-makers the foreparts and the shanks of leather outsoles require to be in temper both before and after they are attached. Because of these reasons it is common practice to temper unattached outsoles throughout their entire" length andbreadth by 'immersing' them in a tempering liquid such as water or-a solution containing water and one or more other ingredients. Such immersion is usually followed by a long period of mulling to enable capillary action to distribute the absorbed 15. tempering liquid uniformly throughout the soles.

While this practice has the desired tempering effect it also produces certain detrimental effects with respect to shoes provided with heels thatdonot mask the perimeters of'the heel-seat portions of the outsoles but liewhollyon the'outer faces' of thelatter. These detrimental effects. are due, I

have ascertained, to the presence of too much it the tempered leather will not gripthe fastenersso tightly as dry leather which, being firmer, does not yield so readily to the displacing or dilating force. Thereafter, when the moisture leaves the displaced leather through evaporation this leather does not recover its normal grip on the fasteners but becomes set or hardened in its dilated condition, withthe result that the securing'effect of the fasteners is permanently im paired. V

Moreover, as moisture evaporates fromleather oncetempered, the leather shrinks, and the extent of shrinkage is virtually proportional to' the quantitylof moisture absorbed by the leather.

This effect becomes apparent if the usual heelfinishing operations have been performed, as they usually are, before much. of the-tempering moisture has evaporated from the heel-seat of the outsole. In the course of normal procedure in a shoe-factory the heel-trimming, scouring, stain; ing, waxing and buffing operations follow so soon after the sole-attaching operation that much of. the shrinking of theheel-seat portion. of the outsole takes place after the final. finishing opera- Application June 25, 1936, Serial No. 87,255

tion, and not only cracks the finish but forms a perceptible ridge or shoulder where the heel projects beyond the contracted perimeter of the outsole.

vide improvements in methods of treating outsoles which will avoid these and other detrimental effects of excessive moisture in the heel-seat portions of outsoles, without sacrificing the benefits of tempering other portions. 1 10:

. invention comprehends the use, for the first step,

of any substance that will protect the selected portion of the sole from the effects of the tempering liquid used in the second step, irrespective of whether the-protective substance itself permeates the selected portion much or little or remains wholly on the surfaces thereof. However, with regard to other considerations, I prefer a protective substance that will quickly impregnate the 25} sole and not militate against any subsequent operation.

Moreover, in the same broad sense, the invention comprehends applying the protective substance in any manner whatsoever. Nevertheless,

since paraffin is a highly satisfactory waterproofing substancejand since it hasother desirable characteristics hereinafter explained; I prefer to liquefy a suitable quantity of parafiin and to apply a small quantity thereof to a selected 5 portion of a sole by immersing that portion only in the liquefied paraffin for a few seconds. This will be sufiicient for all practical purposes, since complete or thorough impregnation is not necessary to accomplish the desired results. Sincethe 4O portion thus immersed will be hot when withdrawn from its bath of paraffin it will quickly shed and absorb nearly all the parafiin on its surfaces, with the result that no paraffin will be apparent on the surfaces when the portion so treated returns to a normal temperature.

Still referring to the aforesaid broader aspect of the invention, but to the second step of the method, the invention comprehends applying the 50 tempering liquid in any manner whatsoever, but since the first step of the method will render the selected portion of a sole highly resistant, if not quite per cent impervious, to a tempering liquid the entire sole may be immersed'there- 55 It isan object of the present invention to pro- 5- after in the tempering liquid without detrimental effect upon the portion first treated.

A typical example of procedure in a shoe-factory for utilizing the method herein set forth may be as follows. Assuming that the outsoles about to be treated have been cut approximately to final size and contour to provide for accuracy in determining how much of their length is to be treated first, one or more soles may be lowered, heel-ends down, into liquefied paraffin in a heated receptacle. Preferably, this will be done by means of some apparatus that will control the depth of immersion with regard to the breast-lines of the soles, to the end that the breast-lines shall descend nearly if not quite to the level of the parafiin.

This primary immersion need not continue longer than a few seconds to obtain sufficient impregnation for the purposes in View and to heat the immersed portions sufficiently to insure free draining and absorption of the paraffin on their surfaces when they are removed from the bath of paraffin. Upon removal of the soles from the bath the soles will cool quickly but not before the' paraffin retained by surface tension is carried into the leather by capillary action. All this takes place so quickly that the soles may be stacked or otherwise handled without appreciable delay.

From this stage the soles may proceed to the tempering stage. In many factories water alone is used to temper soles, while in others tempering solutions or emulsions containing water and other liquids are used. Moreover, various types of tempering apparatus now in commercial use may be used, according to individual preference. However, in the interest of both quality and quantity of production I advocate the use of tempering apparatus of the type illustrated and described in an application for Letters Patent of the United States Serial No. 661,264, filed March 17, 1933 by Fickett, Foreman and Arthur, since the hydraulic pressures obtainable with an apparatus of that type eliminate the need of mulling and bring the soles to a condition suitable for laying in a few minutes.

Proceeding on that basis, the soles now about to be tempered are entirely immersed in a tempering liquid in a receptacle designed to sustain high internal pressures and provided with a closure of like character. While the soles are immersed in the tempering liquid the pressure of the latter may be raised to any desired degree and the latter may be maintained for any desired length of time. The tempering liquid will not, of course, contain anything that would dissolve or melt the moisture-resisting substance, and if the portions first treated do absorb any of the tempering liquid the quantity of the latter so absorbed will be too little to have any objectionable result. Moreover, some of the air initially in the pores of the selected portions first treated will become permanently trapped therein by the moisture-resisting substance, and the air thus entrapped will, itself, resist the entrance of tempering liquid into those portions of the soles.

Although the surfaces of well tempered soles may appear to be dry within a few hours after exposure to the air, the actual temper, even when water alone is used for tempering, will continue much longer, since the moisture in the interior of the soles does not evaporate readily. Consequently, well tempered soles will remain in temper through a period of time long enough for the various operations that follow, including solelaying, heel-seat fastening, channeling, stitching,

channel-cementing, channelclosing, leveling, heel-attaching, heel-trimming, edge-trimming, scouring, staining, waxing and bufiing.

Reverting to the first step of the improved method herein set forth, and specifically to performing that step by impregnating the heel-seat portions of soles with melted paraffin, it has been demonstrated that such treatment, because of .certain characteristics of paraffin not yet spec'- fied, is beneficial not only to the shoes themselves but also to certain shoe-making operations above mentioned.

Leather impregnated with paraifin, particularly the flesh side thereof, is harder and firmer than non-impregnated leather and leather impregnated only with a tempering liquid. Consequently a heel-seat impregnated with parafiin provides a firmer foundation for a heel and improves the work of heel-attaching machines. Moreover, this increase of firmness continues undiminished throughout the life of a shoe.

Again, the presence of paraffin in a heel-seat, and particularly in the fieshy part thereof, produces a marked improvement in the quality of the heel-trimming and randing work in that it causes the normally soft and spongy side of the heel-seat to stand up firmly to the operation of a randing cutter. Consequently the randing will be more even and the product free from fuzz. Moreover, the paraffin encountered by the randing cutter has a lubricating effect that increases the smoothness of cutting and reduces the dulling effect on the cutting edges.

Having thus described the invention, what I claim as new and desire to secure by Letters Patent of the United States'is:

1. That improvement in methods of treating unattached leather soles which consists in first treating a certain portion only of a sole' with a moisture-resisting substance, and thereafter treating another portion of the sole with a tempering liquid.

2. That improvement in methods of treating unattached leather soles which consists in first treating a certain portion only of a sole witha moisture-resisting impregnant, and thereafter immersing the entire sole in a tempering liquid.

3. That improvement in methods of treating unattached leather soles which consists in first immersing a certain portion only of a sole in a moisture-resisting liquid, and thereafter immersing all other portions of the sole in a tempering liquid.

4. That improvement in methods of treating unattached leather soleswhich consists in immersing a certain portion only of a sole in a lique fied waterproofing substance adapted to solidify quickly and adhere to the, sole, and thereafter immersing the entire sole in a tempering liquid.

5. That improvement in methods of treating unattached leather soles which consists in immersing the heel-seat portion only of a sole in a liquefied waterproofing impregnant adapted to permeate the pores of the sole and solidify therein, and thereafter immersing the entire sole in a tempering liquid.

6. That improvement in methods of treating unattached leather soles which consists in immersing a certain portion only of a sole in hot melted parafiin, removing the sole from the hot paraffin, permitting surplus paraffin to drain from the sole, and thereafter immersing the entire sole in a tempering liquid at a temperature lower than the melting temperature of paraffin.

"7. That improvement in methods of treating unattached leather soles which consists in immersing the heel-seat portion only of a sole in a bath of hot melted paraffin to'a line approximately coincident with the breast-line of the sole, removing the sole from the bath of paraffin, and thereafter immersing the entire sole in a tempering liquid.

8. That improvement in methods of preparing unattached leather outsoles which consists in first impregnating the heel-seat-portion only of a sole with a liquefied waterproofing impregnant, permitting the impregnant to solidify therein, and thereafter wetting the shank and the forepart of the sole with a tempering liquid.

9. That improvement in methods of preparing unattached leather outsoles which consists in first treating both faces and the perimeter of the heelseat portion only of a sole with a liquefied waterproofing substance, permitting said substance to solidify on the sole, and thereafter tempering the shank and the forepart of the sole with a liquid to which said substance is non-reactive.

10. That improvement in methods of treating unattached leather soles which consists in immersing the heel-seat portion only of an untempered sole in a bath of liquefied waxy substance, removing the sole from said bath, permitting surplus waxy substance to drain from the sole, and thereafter immersing the entire sole in a tempering liquid to which said waxy substance is non-reactive.

7 1 1. That improvement in methods of treating unattached leather soles which consists in first treating a certain portion only of a sole with a moisture-resisting impregnant, thereafter immersing the sole in a tempering liquid, and altering the pressure of the tempering liquid while the sole is immersed therein to speed the tempering effect of such liquid.

WILLIAM P. CROCKETT. 

